Computer systems including personal computers, workstations, hand-held devices, etc. have been utilized in an increasing number of applications at home, the workplace, educational environments, entertainment environments, etc. Peripheral devices of increased capabilities and performance have been developed and continually improved upon to extend the functionality and applications of computer systems. For example, imaging devices, such as printers, have experienced significant advancements including refined imaging, faster processing, and color reproduction.
Error diffusion is a halftoning algorithm which may be used, for example, in digital printing. The error diffusion halftoning algorithm renders different tone levels by adaptively modulating local dot density. The algorithm may implement random dot placement substantially free of Moire artifacts when rendering images having strong periodic components while also achieving relatively high spatial resolution. Accordingly, the error diffusion algorithm may be used to render scanned images which may often have relatively strong embedded periodic screen frequencies.
Error diffusion processing utilizes a relatively significant computational load during processing operations. For example, error diffusion processing may compute and diffuse filtered pixel errors to neighboring pixels in addition to thresholding operations often implemented in screening algorithms. The significant computational load may be a drawback for use in high speed imaging applications.
At least some aspects of the disclosure provide improved apparatus and methods for processing image data.